1. Field of the Invention
The present invention relates to an image input/output apparatus and an image input/output method. More particularly, the present invention relates to an image input/output apparatus in which an image display section and an image input section are integrated into a unit, so that the apparatus is miniaturized and the construction of the apparatus is simplified. The present invention also relates to an image input/output method using the image input/output apparatus.
2. Description of the Related Art
As a conventional image display apparatus, an active matrix type liquid crystal display apparatus is known. FIG. 6 shows an exemplary active matrix type liquid crystal display apparatus. In the active matrix type liquid crystal display apparatus, one of liquid crystal portions 251, 252, . . . and one of thin film transistors (TFTs) 241, 242, . . . are paired so as to constitute a pixel. During the operation, the TFTs in respective rows are turned on or off by a gate drive circuit 200 via corresponding gate lines 211, 212, . . . . Also, data (voltage) is sequentially written into the respective liquid crystal portions 251, 252, . . . by a data drive circuit 202 via corresponding data lines 231, 232, . . . , so as to perform a display.
On the other hand, as an image input apparatus, a contact type image sensor is known. In the contact type image sensor, a one-dimensional sensor array is made so as to have a length which is equal to the width of an original, i.e., original surface to be imaged, and the reflected light from the original surface is detected by the respective sensors in the sensor array. When a two-dimensional original surface is to be read by the contact type image sensor, the image sensor or the original surface is required to be mechanically moved in a direction perpendicular to the sensor array for scanning. In order to eliminate the mechanical movement for scanning, a structure such as that shown in FIG. 7 is proposed. In the structure, pairs of photodetective layers 315 and TFTs 311 are provided in a matrix form on a transparent substrate 301 (for simplicity, only one pair of which is shown in FIG. 7). In FIG. 7, a transparent protecting layer 302 is formed over the entire surface of the transparent substrate 301. Then, a thin glass plate 303 is provided on the transparent protecting layer 302. In this image input apparatus, an original surface 313 is illuminated by light 312 incident from the side on which the transparent substrate 301 is provided. Then, the reflected light 314 from the original surface 313 is detected by the photodetective layer 315 which converts the detected light into an electric signal. The converted electric signal is supplied via the TFTs to a scanning circuit (not shown), and taken out by the scanning circuit as a time-series signal.
As described above, conventionally, the image display and the image input are separately performed by different types of apparatus. For example, in a work station or a personal computer, a display is provided independently of an image reader and a scanner. The connection therebetween is realized via an interface.
In recent years, small-sized computers have been manufactured, so that there is a requirement for peripheral image input/output apparatus to be compact in size. However, according to the prior art as described above, the image display and the image input are separately performed by different types of apparatus, which prevents the image input/output apparatus from being miniaturized. Moreover, both the apparatus necessitate their own scanning circuits, respectively. This causes a problem in that the construction of the apparatus cannot be simplified. Especially in the case of a two-dimensional image sensor, it is necessary to scan the photodetective layers which are provided separately for respective pixels, and it is necessary to provide an optical system (a lens, or the like) for illuminating an original surface. Therefore, the construction of the two-dimensional image sensor is complicated.